Sonic's multiverse is vast & the amount of alternate versions of our favorite blue hero is always growing. One version of Sonic comes in the form of Scourge The Hedgehog. Previously only known to the rest of the multiverse as "Evil Sonic" or "Anti Sonic", This Sonic comes from a world where his father was born into royalty, making him the next in line for the throne when he came of age. His father brought about a period of absolute peace across the planet, but eventually something happened that caused the whole system to fall apart. This Sonic wasn't particular fond of the peace his father brought about anyway, & was actively rebelling against it in the same way Sonic Prime rebels against the efforts of Dr. Eggman.
Anti Sonic's impatience for the throne & strained familial relationship brought him to the decision to kill his father & bring about a world of madness under his rule. Eventually, Anti Sonic put together a team of fellow rebels & travelled the globe with them on a massive crime spree. Eventually, this Sonic grew bored of his world & discovered the Cosmic Interstate, a gateway to the multiverse, where he realized that he was nothing more than an alternate version of another Sonic. This ticked him off, & he set out to prove himself superior & make a new name for himself.
Soon after traveling to the Archie Sonic Dimension, he teams up with the jewel-hungry Rouge The Bat & locates the Master Emerald. Before Knuckles' father could intervene, Anti Sonic used the Master Emerald's power to give himself a new form. Knuckles' father Locke swipes him off of the Emerald before he could continue, leaving a scar on the hedgehog's torso. The new look, combined with an increase in speed & power, gave him the idea to go by the new name, Scourge The Hedgehog.
Currently, Scourge is teamed up with a mysterious Echidna known as Dr. Finitevus & plotting an invasion of the multiverse. However, it seems as though the plans of Dr. Eggman may put Scourge's idea of a takeover on hold.